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Beavers and the Watertable

heidi08 Educational, Environmental August 13, 2009

Our New Zealand beaver friend, William Hughes-Games, is getting ready for his presentation to the council about the Hurunui dam project, and is doing a lot of thinking about how beavers raise the water table with their dams. I thought his writing was an easily understood overview of this seemingly magical process, and I wanted to pass it along. If you’d like to read it in novel form, go check out the book he introduced me to “Three against the Wilderness” by Eric Collier. It describes in lively detail what happens to the habitat when beavers are reintroduced to the Canadian Wilderness around the turn of the century.

First, how does the beaver increase the amount of effective water?

Beavers make a series of low dams across streams. If unimpeded, water falling in a catchment flows down the stream and river as fast as the slope and stream characteristics allow. All that fresh water goes straight down to the sea. With a beaver dam, there is a pond which is wider than the original steam bed and a water surface which is higher. The pond itself is a store of water. However this is only a minor part of the water storing capacity created by beavers. With the greater surface area of water in contact with the land and the higher water level, water flows into the surrounding water table. Once underground,the water is protected from evaporation. It seeps seaward at a much slower rate than water in the stream and seeps back into the stream further down stream. Instead of a short sharp flood peak, the water is slowed down and spread out over time. .

A fast running stream provides a certain number of ecological niches for a limited number of plants and animals. Beaver ponds and the eventually produced wetlands provide far more niches. As mentioned, beaver dams settle out suspended mineral material and provide clear water. All sorts of plants can take root on the bottoms of these ponds as well as bull rushes around the edges and water lilies somewhat deeper. All these provide habitat for fish, water insects, ducks etc. and watering places for terrestrial animals. The native people of western Canada called the beaver the Sacred Centre of the earth because they understood the tremendous benefits brought by beavers.

I’ll confess, I’m boning up on my beaver facts to get ready for Saturday’s interview. In addition to Williams fantastic analysis, I reread my section on beavers and the environment from the subcommittee report. Not to toot my own instrument here, but dam(n)! that was some nicely referenced writing. I’ve added it to the reports section of the blog, in case someone needs a quick reference for why beavers matter to the habitat.

Great Dams! Shame About the Beavers….

heidi08 Environmental April 9, 2009

Matt Cawood, agricultural writer from Australia, began a series of articles on his blog for Stock and Land entitled “Beavers and the Murray.” In it he extols the book with which I hope by now you are all familiar: Eric Collier’s Three Against the Wilderness. Like others he was interested in the effectiveness of trapping small ponds of water through little dams and how it created a lusher, greener habitat that could withstand even dry periods. I was overly excited by the article, and suggested he might want to get in touch with our New Zealand friend who is talking about this very point with the local magistrate this month. He wrote back with a tone that could be politely described as gubenatorial,

I can’t imagine beavers themselves can or should play any role in Australia’s environment. It’s the principle of slowing water’s flow through the landscape that is interesting.

To paraphrase the Monks…Great Dams! Shame about the Beavers….

Okay so today is part II of his series in which he reveals that his secret to water holding isn’t beavers, its a series of low leaky weirs that hold the water back and an abundance of reeds that help them do so. The water is slowed and filtered, and the water table rises and in the hard rains the land is able to keep some of the aquatic wealth that otherwise pours uselessly out to the sea. He wonders what would the effect have been if such dams had been built on miles of wetlands 20 years ago?

Pointedly, he does not wonder if beavers have any role to play in Australia’s water problems. He also doesn’t wonder about any costs for building or maintaining these “leaky weirs” and whether it would be problematic for human hands to do so over miles of creek bed across the entire country. Another commenter wrote that beavers were reintroduced in South America and look at all the trouble they’ve caused. I guess that means that Australian farmers never prune their trees to make them grow back, because the failure to coppice is what makes the fate of South American trees different, not the lack of eager beaver predators.

Obviously his basic point is that beavers structurally may be onto something, but the beavers themselves are not welcome. Hmm. I wonder how Mr. Collier would feel about that takeaway from his novel?

And the Beaver Goes On…

heidi08 Beaver News, Beavers elsewhere, Environmental March 22, 2009

Remember the book I mentioned called “Three Against the Wildnerness” by Eric Collier? Hopefully some beaver fans got curious enough to pick up a used copy and read for themselves. Well, beaver friend from New Zealand, WHG sent me these photos from Chilcoten (about 100 km from the site in the book) taken by his aunt. Looks like beaver progeny are doing well in Canada.

Lovely dam isn’t it?

Also got a very reassuring email from a beaver friend in Danville Ca that some beavers had “graced them with their presence” in the Danville San Ramon Creek for a while, although they hadn’t been seen lately. Graced them! Danville clearly knows a good thing when they see it.

They got around to it…

heidi08 Educational, Friends of Martinez Beavers August 8, 2008

So last night, when I couldn’t be there, there a was beaver extravaganza on the new cottonwood. Several of our regulars got the full view of family munching on its spoils. There’s a lot more tree to enjoy so if you missed out too you can still catch tonight’s show.

In the mean time I thought I’d get a “Round tuit” also and talk about our good friend William Hughes-Games’ first adventure with beavers.

Now William lives in New Zealand, where they have honey possums and echidne’s but they don’t have beavers. Don’t ask me how he got interested in the industrious creatures, we’re just glad he did. He’s a supporter of Beavers Wetlands and Wildlife and read about our beavers in their newsletter this winter. He is a scholarly-minded fellow who maintains his own blog down under. He has always been particularly interested in the relationship between salmon and beavers. This summer he made a trek to Canada to check all the Salmon hatcheries there.

And he got to see his VERY first beavers in person.

[youtube:http://youtube.com/watch?v=DkWMf-HEq-o]

In the midst of his exciting beaver/salmon safari, he reconnected with an old family member who turned him onto a great read: “Three Against the Wilderness” by Eric Collier. It was published in Canada in 1959 and is the story of an amazing family and their committment to returning beavers to British Columbia in the early 1900’s. The hero and author marries a woman who is a quarter native american. Her very interesting blind grandmother Lala gives the couple a unique life plan.

“Aiya, the beavers! Until white man come indian just kill beaver now an’ then s’pose he want meat or skin for blanket. And then, always the creek is full of beaver. But when white man come and give him tobacco, sugar, bad drink, every tam; he fetch beaver skin from creek Indian go crazy and kill beaver all tam’. What’s matter white man no tell Indian—some beaver you must leave so little ones stop next year? What’s matter white man no tell indian s’pose you take all beaver, blimeby all water go too. And if water go, no trout, no fur, no grass not’ing stop?”

“Why you no go that creek and give it back the beavers? You young man, you like hunt and trap. S’pose once again the creek full of beavers, maybe trout come back. And ducks, and geese come back too, and big marshes be full of muskrats again all same when me little girl. And where muskrats stop, mink and otter stop too. Aiya! Why you no go that creek with Lily and live there all tam’ and give it back the beavers?”

And so off they go, after he is given sole trapping rights of 150,000 acres in the roughest, wildlest lands of Meldrum Creek from headwaters to mouth. To say they encounter (and bravely face) great danger, hardship and sacrifice is putting it midly. After buiding a log cabin, they start by repairing the dams along the drought plagued creek, which gets all its water in the rapid snow melt and loses it to the big river because it can’t trap any to save for itself. There are no beavers to reintroduce because they have all been killed, until a very wise Game Warden gives him two breeding pairs to start things off. The book is an exciting combination of little house on the prairie, Robinson Caruso and “Lost”. It’s out of print but you can pick up a used copy from amazon here. It is a very literal retelling of the Keystone species principal. It is stunning to me that this book has existed for nearly 50 years and there are still discussions about whether beavers are good for the environment.

It was thrilling this summer to read about William’s first beaver encounters. Apparently Canadian beavers are way more stressed out than Martinez beavers. That tail slap is positively jittery! Check out the rest of his furtive beaver footage on his youtube site. Or read about his trip in his own words by visiting his blog here.